The present invention relates to a vacuum pump aspirator for use in conjunction with an engine air pre-cleaner of a work vehicle.
Engine air intake systems for work vehicles typically include a pre-cleaner to remove dirt particles from the intake air prior to the air filter. Many pre-cleaners require a vacuum to pull or xe2x80x9cscavengexe2x80x9d dirt particles from the fresh air ingested into the air intake system. Exhaust system aspirators have been used to supply the required vacuum. An exhaust system aspirator, however, creates a restriction in the engine exhaust, raises noise levels and raises the cost of the muffler and/or exhaust pipe. Also, a check valve is needed to prevent back flow of high temperature gases into the pre-cleaner and high temperature hoses must be used.
An alternative approach is to use a fan shroud aspirator as a source of vacuum to a pre-cleaner. This aspirator is merely an opening in the fan shroud enabling a hose to link with a pre-cleaner. Most radiator fans use a viscous coupling for optimum cooling performance and fuel economy. Depending upon the ambient air, the fan speed does not always match the engine speed. Thus, at times the fan shroud aspirator does not provide sufficient vacuum to the pre-cleaner for the engine intake air requirements.
The present invention overcomes the disadvantages described above by providing a belt driven vacuum pump coupled to the pre-cleaner to scavenge dirt particles from the pre-cleaner. The belt driven vacuum pump eliminates the need for the exhaust system aspirator with the restriction in the engine exhaust as well as eliminates the need for numerous and expensive components associated with the exhaust system aspirator. Furthermore, the speed of the belt driven aspirator is solely a function of the engine speed. The vacuum pump speed is not dependent upon fan speed and current engine cooling requirements.
In the preferred embodiment, the vacuum pump is integrated into an accessory support bracket that carries other belt driven accessories such as the alternator, air conditioning compressor, etc. and is driven by a common belt with those accessories. The vacuum pump is integrated into the support bracket by providing a recess in the support bracket itself to house the vacuum pump blade. Air outlets are formed in the support bracket and are preferably directed toward accessories or engine components that can benefit from the additional cooling provided by the airflow.